Concrete Calculator
Calculate cubic yards, cubic meters, and the number of 40, 60, and 80-lb concrete bags for slabs, footings, columns, and stairs. Optional price input gives a full project cost.
Inputs
Result
Volume
1.36 yd³
Metric
1.04 m³
80-lb bags
62
- 60-lb bags
- 82
- 40-lb bags
- 123
- Cubic feet
- 36.7 ft³
- Waste included
- 10%
Waste default: 10% — ACI 301 recommends a 5–10% overage to account for sub-grade variation and spillage.
Diagram
Estimates only. Verify with a licensed contractor or supplier before purchasing. Rough Estimator! is not responsible for shortages, overages, or material variances. See our methodology for formulas and sources.
Formula
Volume (yd³) = L × W × D ÷ 27 · Bags (80 lb) = Volume (ft³) ÷ 0.6
References
Pour-window forecast
Free 7-day forecast from Open-Meteo. Green = safe to concrete. We never share your location.
Related tools & materials
Calculators
Don't forget
- Rebar
- Wire mesh
- Vapor barrier
- Form lumber
- Expansion joint
Frequently asked questions
A 10×10 patio at 4 inches thick needs roughly 1.23 cubic yards (about 51 80-lb bags) including a 10% waste factor.
Cite this page
Cosyslabs. (2026). Concrete Calculator. Rough Estimator!. https://roughestimator.com/concrete-calculator
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